The significance of self-annealing in two-phase alloys processed by high-pressure torsion

6th International Conference on Nanomaterials by Severe Plastic Deformation

材料科学;化学

Zhang, Nian Xian^1 ; Kawasaki, Megumi^2,3 ; Huang, Yi^1 ; Langdon, Terence G.^1,3

Materials Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ, United Kingdom^1

Division of Materials Science and Engineering, Hanyang University, Seoul 133-791, Korea, Republic of^2

Departments of Aerospace and Mechanical Engineering and Materials Science, University of Southern California, Los Angeles CA 90089-1453, United States^3

关键词: Electron back scatter diffraction;    Experimental conditions;    Grain boundary migrations;    Hardness values;    High angle grain boundaries;    High pressure torsions;    Recovery process;    Two-phase alloys;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/63/1/012126/pdf
DOI  :  10.1088/1757-899X/63/1/012126

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

The Zn-22% Al eutectoid alloy and the Pb-62% Sn eutectic alloy were processed by high-pressure torsion (HPT) over a range of experimental conditions. Both alloys exhibit similar characteristics with significant grain refinement after processing by HPT but with a reduction in the hardness values by comparison with the initial unprocessed conditions. After storage at room temperature for a period of time, it is shown that the microhardness of both alloys gradually recovers to close to the initial unprocessed values. Electron backscatter diffraction (EBSD) measurements on the Pb-Sn alloy suggest that the self-recovery behaviour is correlated with the fraction of high-angle grain boundaries (HAGBs) after HPT processing. Thus, high fractions of HAGBs occur immediately after processing and this favours grain boundary migration and sliding which is important in the self-annealing and recovery process. Conversely, the relatively lower fractions of HAGBs occurring after annealing at room temperature are not so conducive to easy migration and sliding.